1. Field of the Invention
This invention relates to recliner means for allowing a seat back of a vehicle seat to be pivoted or inclined relative to a seat cushion of the vehicle seat by manually operating an operating lever for the recliner means, and a vehicle seat provided with the recliner means in which changing of a posture of the seat back from a forwardly inclined posture to a predetermined standing posture, or returning of the seat back to a predetermined point can be carried out without operating the operating lever and continuing holding of the operating lever.
2. Description of the Prior Art
Referring now to FIGS. 1 to 8, a conventional recliner device will be discussed hereinafter in order to facilitate understanding of the present invention.
Referring to FIG. 1, the conventional recliner device comprises a disc-like housing 10, a disc-like cover 11 rotatably fitted in the housing 10 in a face-to-face relation with the housing 10, a pair of latches 12, 12′ arranged within the housing 10 and movable between locked positions and unlocked positions or in a radial direction of the cover 11 fitted in the housing 10, a cam 13 arranged within the housing 10 for causing the latches 12, 12′ to be displaced toward the locked positions, two spiral springs 14, 14′ arranged within the housing 10, a cam disc 15 integrated with the cam 13, and an actuating shaft 16 penetrating the housing 10 and the cover 11. The cam 13 and the cam disc 15 are integrally fixed on an axis of the actuating shaft 16.
Referring to FIG. 2, the disc-like housing 10 comprises a circular plate-like body 10a′ and an annular wall portion 10a rising up from a peripheral edge of the circular plate-like body 10a′. An inner surface of the circular plate-like body 10a′ is provided with two pairs of guide blocks 10b, 10c, 10b′, 10c′ for supporting the latches 12, 12′ from both sides of the latches 12, 12′ so as to allow the latches 12, 12′ to be slid on the inner surface of the circular plate-like body 10a′, and support pins 10d, 10d′ to which innermost ends of the spiral springs 14, 14′ are to be fastened when the recliner device is assembled. The circular plate-like body 10a′ is formed with a bearing hole 10e at a central portion of the circular plate-like body 10a′, through which the actuating shaft 16 is to be inserted when the recliner device is assembled. Furthermore, the circular plate-like body 10a′ is provided with a plurality of hollow projections 10f that extend through the full thickness of the plate-like body 10a′ from the inner surface of the plate-like body 10a′ and project from an outer surface of the plate-like body 10a′. The projections 10f are to be welded to a bracket plate of a seat cushion frame when the recliner device is mounted to the vehicle seat.
Referring to FIG. 3, the disc-like cover 11 comprises a circular plate-like body 11a′ and an annular wall portion 11a rising up from a peripheral edge of the circular plate-like body 11a′. The cover 11 is to be fitted in the housing 10 in a face-to-face relation with the housing 10 when the recliner device is assembled. An outer diameter of the annular wall portion 11a of the cover 11 is smaller than an inner diameter of the annular wall portion 10a of the housing 10, so that the cover 11 is rotatable relative to the housing 10. Gear teeth 11b are formed around an inner periphery of the annular wall portion 11a of the cover 11. The circular plate-like body 11a′ of the cover 11 has a bearing hole 11c which is formed in a central portion of the circular plate-like body 11a′ and through which the actuating shaft 16 is to be inserted when the recliner device is assembled. Furthermore, the circular plate-like body 11a of the cover 11 has a plurality of hollow projections 11d that extend through the full thickness of the plate-like body 11a′ from an inner surface of the plate-like body 11a′ and project from an outer surface of the plate-like body 11a′. The hollow projections 11d are to be welded to a side plate of a seat back frame when the recliner device is mounted to the vehicle seat.
Referring to FIG. 4, each of the latches 12, 12′ is in the form of a substantially quadrilateral plate. The latches 12, 12′ are to be arranged within the housing 10 and are to be supported from the both sides thereof by the guide blocks 10b, 10c, 10b′, 10c′ of the housing 10 so as to be slid on the inner surface of the circular plate-like body 10a′ of the housing 10. The latches 12, 12′ have gear teeth 12a, 12a′ formed at regions of peripheries thereof. The gear teeth 12a, 12a′ of the latches 12, 12′ are adapted to be releasably meshed with the gear teeth 11b of the cover 11 at the locked positions. The latches 12, 12′ further have steped receiver jaw portions 12b, 12b′ provided at regions of the peripheries thereof which are opposite the regions of the peripheries of the latches 12, 12′ at which the gear teeth 12a, 12a′ are formed. The receiver jaw portions 12b, 12b′ of the latches are adapted to receive the cam 13. Furthermore, the latches 12, 12′ are provided with inducting pins 12c, 12c′ that stand up from general surfaces of the latches 12, 12′ and are to be inserted through substantially ellipse-shaped guide holes of the cam disc 15 which will be discussed in greater detail hereinafter.
Referring to FIG. 5, the cam 13 is in the form of a plate and includes pusher edges 13a, 13a′ for pushing the latches 12, 12′ toward the locked positions, receiving edges 13b, 13b′ adapted to be abutted against the latches 12, 12′ at the unlocked positions, and stopper edges 13c, 13c′ with which outermost ends of the spiral springs 14, 14′ are to be engaged. The pusher edges, the receiving edges, and the stopper edges are continuously connected to one another through curved regions. The cam 13 is formed with a stopper hole 13d of a quadrilateral shape in which a bearing piece 16a of a quadrilateral shape having a through-hole (see FIG. 1) is to be fitted. The actuating shaft 16 is to be fitted through the bearing piece 16a mounted in the stopper hole 13d of the cam 13. The cam 13 is further provided with two spaced apart projections 13e, 13e′ which stand up from a general surface of the cam 13 and between which the stopper hole 13d is interposed. The projections 13e, 13e′ of the cam 13 serve as means to integrally mount the cam 13 to the cam disc 15.
Referring to FIG. 6, the cam disc 15 is in the form of a circular plate and formed with the substantially ellipse-shaped guide holes 15a, 15a′ which are spaced apart from each other through a center of the cam disc 15. Each of the guide holes 15a, 15a′ is formed in the cam disc 15 so as to obliquely extend from a region of the cam disc 15, which is adjacent the periphery of the cam disc 15, to a region of the cam disc 15 which is remote from the periphery of the cam disc 15. The guide holes 15a, 15a′ have first hole ends 150, 150′ which are located at regions of the cam disc 15 which are adjacent the periphery of the cam disc 15, and second hole ends 151, 151′ which are located at regions of the cam disc 15 which are adjacent the center of the cam disc 15. The first hole ends 150, 150′ positionally correspond to the locked positions. The second hole ends 151, 151′ positionally corresponds to the unlocked positions. As briefly discussed above, the inducting pins 12c, 12c′ of the latches 12, 12′ are inserted through the guide holes 15a, 15a′ of the cam disc 15. When the inducting pins 12c, 12c′ of the latches 12, 12′ are located at the first hole ends 150, 150′ of the guide holes 15a, 15a′, the gear teeth 12a, 12a′ of the latches 12, 12′ are meshed with the gear teeth 11b of the cover 11. When the inducting pins 12c, 12c′ of the latches 12, 12′ are located at the second hole ends 151, 151′ of the guide holes 15a, 15a′, the gear teeth 12a, 12a′ of the latches 12, 12′ are disengaged from the gear teeth 11b of the cover 11. Furthermore, the cam disc 15 is formed with a first stopper hole 15b of a quadrilateral shape in which the bearing piece 16a is to be fitted, and second stopper holes 15c, 15c′ in which the projections 13e, 13e′ of the cam 13 are to be fitted.
Referring to FIG. 7, the actuating shaft 16 comprises a receiving portion 16b in which an operating lever (not shown) for actuating the recliner device is to be mounted, a collar portion 16c which is to be applied onto the outer surface of the circular plate-like body of the housing 10, a first axial portion 16d which is to be inserted through the bearing hole 10e of the housing, a second axial portion 16e which is to be fitted through the through-hole of the bearing piece 16a fitted in the holes 13d, 15b of the cam 13 and cam disc 15 and which is to be inserted in the bearing hole 11c of the cover 11, and a third axial portion 16f which is to be projected outwardly from the cover 11 and is to be connected to one end of a supporting shaft (not shown). The bearing piece 16a is formed independently from the actuating shaft 16.
The cam 13 is to be integrally fixed to the cam disc 15 by causing the projections 13e, 13e′ of the cam 13 to be fitted into the second stopper holes 15c, 15c′ of the cam disc 15. The bearing piece 16a is to be fitted in the stopper holes 13d, 15b of the cam 13 and cam disc 15. An assembly comprising the bearing 16a, the cam 13, and the cam disc 15 is to be integrally fixed on the actuating shaft 16, so that when the actuating shaft 16 is rotated by the operating shaft, the assembly is rotated.
Referring to FIG. 8, assembling of the recliner device will be discussed hereinafter. The third axial portion 16f (see FIG. 7) of the actuating shaft 16 is inserted through the bearing hole 10e of the housing 10 from the outer side of the housing 10, the first axial portion 16d (see FIG. 7) of the actuating shaft 16 is inserted through the bearing hole 10e of the housing 10, and the collar portion 16c (see FIG. 7) of the actuating shaft 16 is applied onto the outer surface of the circular plate-like body of the housing 10, whereby the housing 10 is mounted on the actuating shaft 16. The latches 12, 12′ are arranged within the housing 10 and supported from the both sides of the latches 12, 12′ by the guide blocks 10b, 10c, 10b′, 10c′ so as to be radially slid on the plate-like body 10a′ of the housing 10 between the locked positions and the unlocked positions.
The assembly comprising the cam 13, the cam disc 15, and the bearing piece 16a is mounted on the second axial portion 16e of the actuating shaft 16 through the through-hole of the bearing piece 16a, with the cam 13 being arranged between the latches 12, 12′. The inducting pins 12c, 12c′ of the latches 12, 12′ are inserted through the first hole end portions 150, 150′ of the guide holes 15a, 15a′ of the cam disc 15 which correspond to the locked positions of the latches 12, 12′. The spiral springs 14, 14′ are arranged within the housing 10, retained between the cam 13 and the support pins 10d, 10d′ of the housing 10, and always bias the cam 13 so as to cause the cam 13 to displace the latches 12, 12′ towards the locked positions.
The cover 11 is rotatably mounted on the actuating shaft 16 through the bearing hole 11c (see FIG. 3), and combined with the housing 10 with the wall portion 11a thereof being received in the wall portion 10a of the housing 10 so as to be rotatable relative to the housing 10. In the assembled condition of the recliner device, the gear teeth 12a, 12a′ of the latches 12, 12′ are meshed with the gear teeth 11b of the cover 11 by the cam 13 that is always urged by the spiral springs 14, 14′, whereby the cover 11 is prevented from being rotated relative to the housing 10.
Referring to FIG. 9, two recliner devices 1, 1 that are constructed as described above are provided at pivotal points between side plates 2a of the seat back frame 2 and bracket plates 3a of the seat cushion frame. The recliner devices 1, 1 are coupled to each other through the supporting shaft which is connected at both ends thereof to the actuating shafts of the recliner devices 1, 1, whereby the recliner devices 1, 1 are adapted to be synchronously actuated. The operating lever 5 is provided at the actuating shaft of one of the recliner devices 1, 1.
Referring to 10, spiral tension springs 6 (only one tension spring 6 is shown in FIG. 10) are provided between the side plates 2a of the seat back frame 2 (only one side plate 2a is shown in FIG. 10) and the bracket plates 3a of the seat cushion frame (only one bracket plate 3a is shown in FIG. 10). A coil spring 7 is stretched between the operating lever 5 and the bracket plate 3a. When the operating lever 7 is rotated or pulled upwardly, the recliner devices 1, 1 are adapted to be brought to unlocked conditions. In the unlocked conditions, an angle of a seat back relative to a seat cushion can be adjusted and the seat back can be pivoted or inclined forward and rearward.
Referring to FIG. 11, the operation of each of the recliner devices will be described in detail hereinafter. When a person rotates the operating lever 5 in a direction while holding the operating lever 5 by hand, the assembly comprising the cam 13, the bearing piece 16a, and cam disc 15 which are integrally fixed on the actuating shaft 16 is rotated. At this time, the guide holes 15a, 15a′ of the cam disc 15 are moved relative to the inducting pins 12c, 12c′ of the latches 12, 12′. As the guide holes 15a, 15a′ of the cam disc 15 are moved relative to the inducting pins 12c, 12c′, the inducting pins 12c, 12c′ arrive at the second hole ends 151, 151′ of the guide holes 15a, 15a′ of the cam disc 15 which correspond to the unlocked positions of the latches 12, 12′, whereby the latches 12, 12′ are displaced so as to be disengaged from the gear teeth 11b of the cover 11. As a result, the cover 11 is brought to an unlocked condition where the cover 11 becomes rotatable relative to the housing 10.
As long as the person still holds the operating lever 5, the unlocked condition is maintained and the seat back is allowed to be inclined forward and rearward relative to the seat cushion. If the operating lever 5 is released from the person's hand, the latches 12, 12′ are urged toward the locked positions by the cam 13 due to actions of the spiral springs 14, 14′, whereby the gear teeth 12a, 12a′ of the latches 12, 12′ are operatively meshed with the gear teeth 11b of the cover 11. As a result, the cover 11 is brought to a locked condition where the cover 11 is prevented from being rotated relative to the housing 10.
In the conventional recliner device, as long as the operating lever is still held by the person in the unlocked condition of the cover, the seat back is allowed to be inclined or folded forward and rearward relative to the seat cushion. In other words, in order that the person can cause the seat back to be inclined relative to the seat cushion in the unlocked condition, the person must continue holding the operating lever. In addition, bringing of the seat back to a normal standing posture relative to the seat cushion is forced to be performed with resort to visual judgement by the person. Furthermore, the tension springs are stretched between the side plates of the seat back frame and the bracket plates of the seat cushion frame as discussed above, so that as soon as the gear teeth of the latches are disengaged from the gear teeth of the cover, the seat back is collapsed excessively forward due to the actions of the tension springs. Therefore, any additional stopper is required for restricting the excessively forward collapsing of the seat back (Japanese Patent Application Laid-Open No. 2002-10850).